Are noise and air pollution related to the incidence of dementia? A cohort study in London, England

Objective To investigate whether the incidence of dementia is related to residential levels of air and noise pollution in London.Design Retrospective cohort study using primary care data.Setting 75 Greater London practices.Participants 130 978 adults aged 50–79 years registered with their general pr...

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Main Authors: Derek G Cook, Frank J Kelly, Iain M Carey, H Ross Anderson, David P Strachan, Richard W Atkinson, Sean D Beevers, David Dajnak, John Gulliver
Format: Article
Language:English
Published: BMJ Publishing Group 2018-09-01
Series:BMJ Open
Online Access:https://bmjopen.bmj.com/content/8/9/e022404.full
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author Derek G Cook
Frank J Kelly
Iain M Carey
H Ross Anderson
David P Strachan
Richard W Atkinson
Sean D Beevers
David Dajnak
John Gulliver
author_facet Derek G Cook
Frank J Kelly
Iain M Carey
H Ross Anderson
David P Strachan
Richard W Atkinson
Sean D Beevers
David Dajnak
John Gulliver
author_sort Derek G Cook
collection DOAJ
description Objective To investigate whether the incidence of dementia is related to residential levels of air and noise pollution in London.Design Retrospective cohort study using primary care data.Setting 75 Greater London practices.Participants 130 978 adults aged 50–79 years registered with their general practices on 1 January 2005, with no recorded history of dementia or care home residence.Primary and secondary outcome measures A first recorded diagnosis of dementia and, where specified, subgroups of Alzheimer’s disease and vascular dementia during 2005–2013. The average annual concentrations during 2004 of nitrogen dioxide (NO2), particulate matter with a median aerodynamic diameter ≤2.5 µm (PM2.5) and ozone (O3) were estimated at 20×20 m resolution from dispersion models. Traffic intensity, distance from major road and night-time noise levels (Lnight) were estimated at the postcode level. All exposure measures were linked anonymously to clinical data via residential postcode. HRs from Cox models were adjusted for age, sex, ethnicity, smoking and body mass index, with further adjustments explored for area deprivation and comorbidity.Results 2181 subjects (1.7%) received an incident diagnosis of dementia (39% mentioning Alzheimer’s disease, 29% vascular dementia). There was a positive exposure response relationship between dementia and all measures of air pollution except O3, which was not readily explained by further adjustment. Adults living in areas with the highest fifth of NO2 concentration (>41.5 µg/m3) versus the lowest fifth (<31.9 µg/m3) were at a higher risk of dementia (HR=1.40, 95% CI 1.12 to 1.74). Increases in dementia risk were also observed with PM2.5, PM2.5 specifically from primary traffic sources only and Lnight, but only NO2 and PM2.5 remained statistically significant in multipollutant models. Associations were more consistent for Alzheimer’s disease than vascular dementia.Conclusions We have found evidence of a positive association between residential levels of air pollution across London and being diagnosed with dementia, which is unexplained by known confounding factors.
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spelling doaj-art-066847a6beae404dbcb18cbca2032e4f2025-02-09T07:00:10ZengBMJ Publishing GroupBMJ Open2044-60552018-09-018910.1136/bmjopen-2018-022404Are noise and air pollution related to the incidence of dementia? A cohort study in London, EnglandDerek G Cook0Frank J Kelly1Iain M Carey2H Ross Anderson3David P Strachan4Richard W Atkinson5Sean D Beevers6David Dajnak7John Gulliver81 Population Health Research Institute, St George`s, University of London, London, UK2 MRC-PHE Centre for Environment and Health, King’s College London, London, UK1 Population Health Research Institute, St George’s, University of London, London, UK1 Population Health Research Institute, St George’s, University of London, London, UK1 Population Health Research Institute, St George’s, University of London, London, UK1 Population Health Research Institute, St George’s, University of London, London, UK2 MRC-PHE Centre for Environment and Health, King’s College London, London, UKMRC Centre for Environment and Health, Imperial College London, London, UKSt George`s University of London, London, UKObjective To investigate whether the incidence of dementia is related to residential levels of air and noise pollution in London.Design Retrospective cohort study using primary care data.Setting 75 Greater London practices.Participants 130 978 adults aged 50–79 years registered with their general practices on 1 January 2005, with no recorded history of dementia or care home residence.Primary and secondary outcome measures A first recorded diagnosis of dementia and, where specified, subgroups of Alzheimer’s disease and vascular dementia during 2005–2013. The average annual concentrations during 2004 of nitrogen dioxide (NO2), particulate matter with a median aerodynamic diameter ≤2.5 µm (PM2.5) and ozone (O3) were estimated at 20×20 m resolution from dispersion models. Traffic intensity, distance from major road and night-time noise levels (Lnight) were estimated at the postcode level. All exposure measures were linked anonymously to clinical data via residential postcode. HRs from Cox models were adjusted for age, sex, ethnicity, smoking and body mass index, with further adjustments explored for area deprivation and comorbidity.Results 2181 subjects (1.7%) received an incident diagnosis of dementia (39% mentioning Alzheimer’s disease, 29% vascular dementia). There was a positive exposure response relationship between dementia and all measures of air pollution except O3, which was not readily explained by further adjustment. Adults living in areas with the highest fifth of NO2 concentration (>41.5 µg/m3) versus the lowest fifth (<31.9 µg/m3) were at a higher risk of dementia (HR=1.40, 95% CI 1.12 to 1.74). Increases in dementia risk were also observed with PM2.5, PM2.5 specifically from primary traffic sources only and Lnight, but only NO2 and PM2.5 remained statistically significant in multipollutant models. Associations were more consistent for Alzheimer’s disease than vascular dementia.Conclusions We have found evidence of a positive association between residential levels of air pollution across London and being diagnosed with dementia, which is unexplained by known confounding factors.https://bmjopen.bmj.com/content/8/9/e022404.full
spellingShingle Derek G Cook
Frank J Kelly
Iain M Carey
H Ross Anderson
David P Strachan
Richard W Atkinson
Sean D Beevers
David Dajnak
John Gulliver
Are noise and air pollution related to the incidence of dementia? A cohort study in London, England
BMJ Open
title Are noise and air pollution related to the incidence of dementia? A cohort study in London, England
title_full Are noise and air pollution related to the incidence of dementia? A cohort study in London, England
title_fullStr Are noise and air pollution related to the incidence of dementia? A cohort study in London, England
title_full_unstemmed Are noise and air pollution related to the incidence of dementia? A cohort study in London, England
title_short Are noise and air pollution related to the incidence of dementia? A cohort study in London, England
title_sort are noise and air pollution related to the incidence of dementia a cohort study in london england
url https://bmjopen.bmj.com/content/8/9/e022404.full
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